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EXCRETION RATE OF ZN 65 BY LITTORINA IRRORATA IN RELATION TO TEMPERATURE AND BODY SIZE 1
Author(s) -
Mishima Jiro,
Odum Eugene P.
Publication year - 1963
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1963.8.1.0039
Subject(s) - excretion , chemistry , tracer , zoology , ingestion , ecology , environmental chemistry , biology , biochemistry , physics , nuclear physics
Excretion of tracer amounts of Zn 65 (in terms of biological half‐life) was followed in 3 sizes of Littorina irrorata at 3 constant temperatures in the laboratory and under field conditions in the natural habitat for a period of 39 days following the ingestion of a single dose. The general pattern of elimination could be resolved into 2 exponential phases, an early rapid loss phase for the first 10 days and a much less rapid loss phase thereafter. Biological half‐life of the “assimilated pool” of the second phase varied inversely with body size and directly with air temperature. Individuals in the field excreted the tracer more rapidly than those confined to glass bowls in the laboratory. Analysis of variance showed that both environmental conditions and body size had a highly significant effect on the excretion rate. Furthermore, trends in relation to temperature paralleled the expected rate of O 2 consumption as calculated from data obtained in a previous study. It is tentatively concluded that, after the non‐assimilated tracer has been eliminated in the early phase, Zn 65 becomes sufficiently bound to the biomass so that the whole body rate of excretion reflects rate of activity of the individual. Since body retention of a gamma‐emitter can be easily determined in the field by periodic recapture and whole body counts, this technique may provide an index to the long‐term rate of metabolism which can not be measured directly in free‐living animals.